Making A Yeast Starter

[dreamboat]

Well, I was dealing with a swollen wyeast pack tonight, and I figured that I would keep a record as I went to post on the forum.
This may be of interest, as I make my starters without the use of a stirrer - some may argue that I have gone beyond the stirrer stage, but as I had the gear to build this setup to hand, I figured that I would try it this way.

First up, here is the basis of my system. This is a tube within a tube setup, similar I would imagine to the way a commercial beer keg operates, but somewhat in reverse. The centre stem is my air in line, and the outer stem, and the branch off the tee, are for air out.



Note the stainless steel airstone on the end of the centre stem.

Now, here is the whole thing setup.... From left to right...
Timer to control the on/off action of the pump
Aquarium Pump
Air filter
Starter with stem inserted
Air out vessel



Benefits of the system over other methods:
Regular addition of air into the starter (not as good as oxygen, but not bad either). If the yeast have available oxygen, they will multiply rather than make alcohol, which is the whole point of a starter.
Timer operation to prevent the starter from foaming over. Timer, pump and airstone are also typically used at the start of fermentation of the beer, again to boost yeast numbers over the first 24 hours or so.
Sealed system. The only way anything gets in, is through the pump and through the filter. I can't recall the rating of the filter, but it is a B3 one, and designed for this type of purpose.
I can scale this system up to whatever I like.... in the pictures, I have 500ml of starter in a 1000ml bottle. I also have a 2 litre and a three litre bottle which I can use to step up the size of the starter if desired.

And here is a picture of the thing running...






Cheers
dreamboat

 

[sintax69]

geez makes my old scotch bottle and jam jar with glad wrap on top look real sad
What is the advantage of this method vs the stir plate method any quicker etc
what size pump is that and how much did it cost I can fell the posties going to be making me a call

 

[sah]

I really like the pipe inside pipe idea.

It'd be a good design for a counter pressure filler too. Or even an in fermenter wort aerator. It could be designed such that the device gets left in place after aeration and takes the place of the airlock or blowoff.

Do you find that the yeast flocculate with this design? They don't with a stir plate.

Nice work.

Scott

 

[Steve]

The technical imagination of some of you guys is amazing!
Onya Dreamboat.
Cheers
Steve

 

[dreamboat]

sintax - pump is a bigW jobbie, probably $15 or less I think. The stone is a 2 micron one, and it is fine, but I would not be sure if that pump could handle a 0.5 micron stone.

sah - yes, the yeast flocculate fine. I believe that I am mimicking a normal fermentation (just higher yeast count) with air at the start of the "ferment", but, I would imagine that after 24 hours of adding air, there is no wort left for consumption and ethanol production.... maybe I am encouraging yeast that multiply, rather than those that have the desired fermentation character???? Hasn't been a problem to date.


dreamboat